Worm drives have been known at least since Leonardo da Vinci draw a sketch of the device in the early 1500s. These mechanisms are efficient at transmitting high torques to the load but present significant shortcomings in applications where a high precision is required in setting the angular position of the shaft, mainly because of play between the parts and/or because of the friction forces manufactured in to reduce play. A typical application of this mechanism as a tuning machine is shown in FIGS. 1 and 2. It consists of a worm (1) which receives the working torque through a button (1A) and is in mesh with a gear (2) attached to a shaft (3) that transmits the resulting higher torque to the load which is the tension of the string (4); a frame (5) that includes two bearings for the worm: a first bearing (6) closer to the button and a second bearing (7) at the tip of the worm, plus one bearing (8) for the shaft, the other bearing for the shaft being provided by a bushing inserted on a hole on the head of the instrument where the tuning machine is installed.